Azo dyes.



UNITED STATES PATENT. OFFICE.

AUGUST BLANK AND WIL'I-IELM BERG-BOLT, OF LEVERKUSEN, NEAR COLOGNE, GER- MANY, ASSIGNORS T0 FARBENFABRIKEN VORM. FRIEDR. BAYER & 00., OF ELBERFEIJ), GERMANY, A CORPORATION OF GERMANY.

Patented Feb. 17, 1914.

A20 DYES.

1,087,429. Specification of Letters Patent.

No Drawing. Application filed March 28, 1913.

Serial No. 757,350.

To all whom it may concern:

Be it known that we, AUcUsT BLANK and lVILHnLM BERGDOLT, doctors of philosophy, chemists, citizens of the German Empire, residing at Leverkusen, near Cologne-on-the- Rhine, Germany, have invented new and useful Improvements in Azo Dyes, of which the following is a specification. Our invention relates to the manufacture and production of new blue azo dyestufis suitable for dyeing half-wool which are distinguished by the valuable property that they dye cotton an intense shade, whereas they leave the wool almost untinged in a neutral dye-bath. The dyeing is carried out in the usual way with an addition of Glaubers salt. The colors dye easily level.

Host of the half-wool or substantive blues hitherto known display the tendency, on being worked for an extended time at the boil, to dye the wool a. deeper shade than the cotton. This is a decided drawback for the dyeing of the half-wool and can be overcome only by regulating the temperature most carefully. This disadvantage is excluded by the use of our new dyes, which always dye the cotton considerably deeper than the wool even when the boiling is continued for a long time, so that the wool can easily be shaded as desired with suitable neutral-dyeing colors.

The process for producing our new dyes consists in combining a tetrazotized para diamin, such as para-phenylenediamin, dianisidin, or para-diaminoazo compounds, such as the tetrazotized intermediate product obtained by the combination of one molecule of diazotized para-amino-acetanilid with one molecule of a naphthylamin sulfonic acid and subsequent saponification and one molecule of a 1.8-.dioxynaphthalene sulfonic acid.

' The new azo coloring matters are in the shape of their alkalin salts after being'dried and pulverized dark poiwders soluble in water with a blue coloration. Upon reduction with stannous chlorid and hydrochloric acid a para-diamin, 1.8-dioxy-2-naphthylamin-sulfonic acid and the mixed urea of 6-amino'-5oxy 2 -naphthylamin '7 sulfonic acid and 2.5.7-amin0naphthol sulfonic acid are obtained. They dye cotton, silk,'artificial silk and half-silk or half-wool blue shades, when applied on the two last mentioned materials they leave the wool or silk almost untinged.

In order to illustrate the new process more fully the following example is given, the parts being by weight :4;3.9 parts of the azo dye obtained from diazotized paraaminoacetanilid and 1.8-dioxynaphthalene- 3.6-disulfonic acid from which the acetyl group is split oil are diazotized with hydrochloric acid and 6.9 parts of sodium nitrite. The resulting diazo compound is then added to a solution of 50.4 parts of the urea of 2- naphthylamin-5-oxy-7-sulfonic acid containing 80 parts of soda, the mixture is stirred during 12 hours, heated to 75 C. and the dye is precipitated with common salt. It dyes cotton pure greenish-blue shades. It is after being dried and pulverwith the urea of 2-naphthylamin-5-oxy-7- ized in the shape of its sodium salt a dark powder soluble in water with a blue color and yielding upon reduction with stannous chlorid and hydrochloric acid para-phenylenedianiin, 1.8-dioxy 2 naphthylainin 3.6- disulfonic acid and the mixed urea of 6- aniino-5-oxy-2naphthylamin-7 -sulfonic acid and 2.5.7-aininonaphthol-sulfonic acid. It has mostprobably the formula (free acid) Y 1 1 l K /v Other 1.8-dioxynaphthalene-sulfonic acids, such as the t-i'nonosulfonic acid may be used.

We claim 1. The herein described new azo dyestuffs, which are in the shape of their alkaline salts, after being dried and pulverized, dark powders soluble in water with a blue coloration; yielding upon reduction with stannous chlorid and hydrochloric acid a para-diamin, a 1.8-dioXy-2-naphthyla1nin sulfonic acid and the mixed urea of G-amino- 5-oXy-2-naphthylamin-7-sulfonic acid and 2.5.7-aminonaphthol sulfonic acid; dyeing cotton, silk, artificial silk, half-silk and half-wool blue shades and being distinguished by the valuable property that on dyeing half-wool they dye cotton an intense shade, whereas they leave the wool almost untinged in a neutral dye-bath, substantially as described.

2. The herein described new azo dye stuff having most probably the formula:

which is after being dried and pulverized in the shape of its sodium salt a dark powder soluble in water with a blue color; yielding upon reduction with stannous chlorid and hydrochloric acid para-phenylenediamin. 1.8 dioxy 2 1 naphthylamin 3.6 disulfonic acid and the mixed urea of 6-an1ino-5-oXy-2- naphthyl-amin-7-sulfonic acid and 2.5.7- aniinonaphthol sulfonic acid; and dyeing cotton in pure greenish-blue shades, substantially as described.

In testimony whereof we have hereunto set our hands in the presence of two subscribing witnesses.

AUGUST BLANK. WILHELM BERGDOLT.

Nitnesses HELEN NUFER, ALBERT NUFER.

L. s. [1,. s]

Copiel of thia patent may be obtained for five cents each, by addressing the Commissioner of Petunia. Washington, D. G. 

